1. Field of the Invention
This invention relates to the combined fields of radiation physics and surface acoustic waves. More particularly, this invention relates to the field of spectroscopy. In still greater particularity, the invention relates to a system for the analysis of optical spectra by a fast scan spectrometer. By way of a specific example, the invention will be described as it pertains to a spectrometer capable of accurate spectral analysis from a moving platform in real time.
2. Description of the Prior Art
Spectrometers have been known in the art for many years. In general, spectrometers have been used to measure indicies of refraction and wavelengths of light by a well-understood relationship of refractive angle and refractive index. Prior instruments designed to scan a spectrum for detection of specific spectral lines are well known and are characterized by U.S. Pat. No. 3,482,105 issued on Dec. 2, 1969 to E. K. Hutzler for "Optical Energy Modulator" and U.S. Pat. No. 3,432,238 issued on Mar. 11, 1969 to A. L. Girard for "Spectrometric Apparatus of High Resolving Power".
Although satisfactory for their intended purpose, the prior art spectrometers have been deficient in their ability to make measurements in limited time frames as might, for example, be occasioned by a moving platform, such as a missile, or a transitory phenomenon, such as an explosive detonation. Principally, these limitations are due to the dependence on physically moving parts to establish the scan of the dispersed spectra. These moving parts have presented problems of synchronism and inertia in the short time frame applications.
Other attempts to solve this problem have employed a plurality of photoelectric detectors in an array extending across the spectral focal plane. Such systems, although inertialess, present problems of calibration and physical spacing to obtain the spectral resolution required for present-day measurements.